1. Field of the Invention
The present invention pertains to vibrator mounting structures and, more particularly, it pertains to a mounting for a vibrator used to excite a two-mass vibratory system.
2. Description of the Prior Art
Vibrators have been used for many years in the industrial field for vibrating working members, such as screens, feeders, conveyors and separators, for example. These vibrators typically are comprised of a rotating shaft having one or more eccentric weights attached thereto for generating a rotating force vector through the bearings which support the shaft and connect it with the surrounding structure.
By far the most common method of mounting such rotary vibrator structures upon the object to be vibrated is the so-called "brute force" system. In such a system, the vibrator supporting structure is mounted directly to the object to be vibrated so that the rotating force vector, such as might be transmitted from an eccentrically weighted shaft, will be passed directly from the supporting bearings to the working member in which a vibratory motion is desired. One common problem with which this typical method of mounting a rotary vibrator is afflicted, is that the direction of the vibratory motion is limited by the manner in which the vibrator is connected to the vibrated object.
In order to obtain relatively linear motion, as opposed to the circular motion normally achieved by the "brute force" vibratory systems, vibrators in recent years, in certain applications, have utilized elastic members which are relatively rigid in the direction in which the vibratory motion is desired to be directed and which are flexible in the transverse direction, so that little, if any, vibratory force is transmitted transversely. A typical example of such a structure is provided by the United States patent to Musschoot U.S. Pat. No. 2,984,339 which discloses a vibratory feeder that includes a set of air springs for mounting the rotary vibrator structure to the conveyor structure.
An even more recent improvement has been the use of elastomeric members for mounting the exciting vibrator to the object to be vibrated. For example, the United States patent to Bruderlein U.S. Pat. No. 3,417,630; Maeder et al U.S. Pat. No. 3,212,629; and Makino U.S. Pat. No. 3,396,294 all disclose rotary vibrator structures which are connected to the object to be vibrated by means of elastomeric blocks.
In U.S. Pat. No. 3,703,236 a mounting to control the direction of vibration in a two-mass system is disclosed.
Vibratory linear motion screens are commonly driven by either of two basic means. The first means comprises a crank arm driven by an eccentric shaft, wherein the crank arm connects either a fixed or resiliently mounted frame to a screen box and thereby imparts motion to the frame or box. The second means comprises counter rotating dual shafts with eccentric weights to oscillate the screen in a direction parallel to a line between the shaft centers or in a direction transverse to said line between the shaft centers depending on the relative orientation of the respective counterweights on the dual shafts.
The patents 3,583,553 and 3,703,236 show two-mass vibratory mechanisms.